Production of seam-like connections between flat fabric members by means of thermoplastic materials



Oct. 17,. 1967 5 KELLER T 3,347,73@

PRODUCTION OF SEAM-LIKE CONNECTIONS BETWEEN FEAT FABRIC MEMBERS BY MEANSOF THERMOPLASTIC MATERIALS O'riginal Filed Dec. 9, 1958 I I 4Sheets-Sheet l r I. k

INVENTOR5 iyfi/d Ke/Zew Kari Emma f BY 4 WI W ATTORNEYS FA if Get. 17,1967 KELLER E 3,347,730

S ['AL= PRODUCTION OF SEAM-LIKE) CONNECTIONS WEEN FLAT FABRIC NS OF THEATE] RIALS 4 Sheets-Sheet 2 RMOPLAS M MEMBERS BY MBA Original Filed Dec.9, 1958 fig. 3a 2 P .3 7W 5 z? fig 56 Z y 22 20 INVENTORS BY JQW,W

ATTORNEYS Get. 17, 196? PRODUCTION OF MEMBERS Original Filed Dec. 9,1958 S. KELLER ETA M-LIKE CO MEANS OF L 3,347,73Q CTION BTWEE LAT FABRICRMOPL 1c M A IALS 4 Sheets-Sheet 5 BY fawz ue W ATTORNEYS Oct. 17, 1967s KELLER ETAL LJIKE CONNECTION 3,347,739 FABRIC PRODUCTION OF SEAM SBETWEEN FLAT MEMBERS BY MEANS OF THERMOPLASTIC MATERIALS Original FiledDec. 9, 1958 4 Sheets-Sheet 4 INVENTOR kg/Wed KeZ er Kur/ Era/2d! BY @44K 6 ATTOPJ EYS United States Patent Ofiice 3,347,73Q Patented Oct. 17,1967 PRODUCTION GF SEAM-LIKE CONNECTEONS BE- TWEEN FLAT FABRIC MEMBERSBY MEANS OF THERMGPLASTIC MATERIALS Siegfried Keiler, Mnnich-Soiln, andKurt Brandt, Augsburg, Germany, assiguors to Messerschmitt A.G.,Augsburg, Germany, a corporation of Germany Original application Dec. 9,1958, Ser. No. 779,145, now Patent No. 3,122,465, dated Feb. 25, 1964.Divided and this application Feb. 21, 1964, Ser. No. 346,535

8 Claims. (Cl. 156-423) This application is a division of co-pendingapplication Ser. No. 779,145, filed Dec. 9, 1958, now Patent No.3,122,465, dated Feb. 25, 1964.

The invention relates to the production of seam-like connection of fiatfabric members, in particular of webs, using thermoplastic masses whichare introduced into common recesses the mass being liquified and thencooled.

A process is already known in which materials suh as webs are connectedtogether by means of thermo plastic foils. In this process, theconnection is effected under pressure and the thermoplastic foil isheated by means of a high frequency field in such a way that itpartially penetrates into the cavities formed by roughening orperforating the material at the points where connection is to beestablished.

' The invention does not use such foils, which appear to be unsuitablefor a number of reasons, and particularly because of the large amount offoil needed and the necessity for roughening or perforating the materialprior to the actual process of connection: furthermore, such foils mustfirst be cut to the required shape and then placed separately betweenthe layers of fabric or the like.

In particular, the invention does not use a single, continuous band orthread of thermoplastic material for forming the actual band.

As a further development of the principal idea, the invention alsorelates to a process for the production of pseudo lock stitches.

It has already frequently been attempted to solve the problem of thelower thread in the lock stitch seams, i.e. to find a way of omittingthe tiresome winding and changing of the shuttle for the lower threadand to make it possible to use considerably larger shuttles for thelower thread. All the attempted solutions have so far failed, however,owing to the fact that in the formation of the lock stitch the loop ofthe needle thread must be taken right round the entire shuttle or storeof the lower thread. The possible size of the rotary hook which carriesthe needle thread around the entire shuttle or store of lower thread islimited, and therefore the maximum size of the shuttle for the lowerthread is also limited.

The invention provides a method which enables a shuttle or roll of anydesired size to be used for the lower thread.

According to the invention, the production of the pseudo lock stitchseam may be carried out by various processes.

Broadly, the invention consists of a process for the manufacture ofseam-like connections in flat flexible fabric members, such as pieces oftextile fabric, which includes the steps of repeatedly forming, as acontinuous process, common recesses in said members at spaced intervals,introducing directly to each recess, after the formation thereof, amass, such as a shaped solid plug of thermoplastic bonding material,liquifying said mass, and allowing same to solidify again, thereby toform a series of localized bonds between said pieces.

The further development of the invention deals with a process forproducing a pseudo lock stitch seam. The essential feature of a lockstitch seam, namely the holding together of the layers of fabric by aneedle thread and a lower thread and the connection of the two threadswith each other inside the layers of the fabric are retained in thisprocess. The difference between the normal lock stitch and the pseudolock stitch produced according to the invention is that in the case ofthe normal seam the needle thread and the lower thread are intertwinedwithin the layers of the fabric whereas in the process of the inventionthe upper and lower threads are connected to each other, usually insidethe layers of fabric, by means of artificial material, in particularthermoplastic resin. No intertwining of the needle thread and the lowerthread takes place in this process and the store of lower thread may bejust as large as that of the needle thread.

A further development of the invention consists in that the bonding ofthe upper to the lower threads by the thermoplastic bonding agent toproduce the pseudo lock stitch seam takes place outside the layers orwebs, the process being thereby greatly simplified and the operation ofsewing becoming very similar to that of sewing normal lock stitch seams.

The invention also includes a supply device for the thermoplasticmaterial.

' The various processes of the invention are explained by way of examplewith reference to various modes of construction shown in the drawings.

The first group of figures show the use of a bonding agent in the formof spheres which are pressed into the fabric from above, thus FIG. 1ashows the phase before the bonding agent is pressed in,

FIG. 1b shows the bonding agent pressed in, and

FIG. 1c shows the bonding agent melted.

The second group of figures show use of a bonding agent in the form ofspheres pressed into the web both from above and from below, thus FIG.2a shows the phase before the bonding agent is pressed in,

FIG. 2b shows the bonding agent pressed in, and

FIG. 20 shows the bonding agent melted.

The third group of figures show the use of a bonding agent in the shapeof studs, pressed into the fabric from above, thus FIG. 3a shows thephase before the bonding agent is pressed in,

' phases in the use of a bonding agent in the form of a continuouslysupplied wire divided into studs for bonding together the upper andlower thread for the purpose of producing a pseudo lock stitch seam anda pseudo single chain stitch seam.

FIG. 7 shows the use of bonding agents in the form of spheres forbonding together the needle thread and the lower thread of a pseudo lockstitch seam.

' FIG. 8 shows the use of bonding agents in the form f of spheres forthe production of a pseudo single chain stitch seam.

FIG. 9 shows a portion of a finished seam and the first working phase inthe formation of the pseudo stitch seam when the needle of the sewingmachine is descend-.

i ing with the upper thread.

FIG. 10 shows a further phase in the process of frm ing the seamaccording to FIG. 9, in which the sewing machine needle has brought theneedle thread through the layers of fabric.

FIG. 11 is a further phase in the operation of making a seam accordingto FIG. 9, in which the upper thread is being bonded to the lowerthread.

FIG. 12 shows the final phase in the process according to FIG. 9 offorming a seam, in which the point'of bonding between the upper and thelower thread is pulled into the layers of the fabric.

FIG. 13 is a view in the directionof the point of bonding between theupper thread and the lower thread of the pseudo lock stitch seamaccording to FIG. 9 before bonding takes place.

FIG. 14 is a plan view in the direction XIV, that is, from above, ofFIG. 10.

The process according to the main idea of the invention is explainedbelow with reference to the first four groups of figures.

As in a sewing machine, in which the needle is moved mechanically or bymeans of electromagnetic driving means, a press pin 2 moves in anozzle-like or sleeve-like housing 1; this pin at the same time acts asmeans for conducting heat or transmitting ultrasonic energy or, ifconnected to a high frequency generator, it may form a part of thecondensor for producing a high frequency alternating field.

When the press pin 2 is raised (FIG. la) a spherical mass of bondingagent 3, preferably of thermoplastic resin, disposed in a magazine orchannel 4 in the housing 1, falls underneath the press pin 2. Layers offabric 5 and 6 which are to be connected are moved on a plate 7 similarto the needle plate of a sewing machine, and thereby comes to lieunderneath the press pin 2. The fabric may be provided with aperforation 8 in a preceding operation step.

When the press pin 2 is lowered (FIG. 1b) the spherical mass of bondingagent 3 is pressed into the layers of fabric 5 and 6, a plate providedin the plate 7 serving as support.

The supporting plate 9 serves at the same time as a means for conductingheat or for the supply of ultrasonic energy, which may, if desired, becontrolled to be intermittent, or alternatively the plate may form acondenser plate connected with a high frequency generator for theproduction of a high frequency alternating field. The spherical mass ofbonding agent 3 is heated by means of heat impulses, ultrasonic waves,or high frequency, and is thereby melted, whereby the bonding agentflows into the layers 5 and 6 of the fabric and connects them togetheron cooling (FIG. 10).

The movement of the layers of Web 5 and 6 on the plate 7 takes placestepwise and is controlled as in a sewing machine, so that the steps maybe short, long, forwards, backwards, to the side or in zig-zag movementetc., so that a row of connecting points are formed which result in aseam-like connection of the layers 5 and 6 to each other.

In FIGS. 2a to 20, in addition to the upper nozzle-like housing 1 withthe press pin 2, a similar housing 10 with a similar press pin 11 arearranged opposite to the former, on the underside of the fabric. Forthis purpose, a plate 12, which carries the layers of fabric 15 and 16,is provided with a recess 13. The bonding agents 3 and 3 are pressedinto the layers of fabric 15 and 16 by means of press pins 2 and 11(FIG. 2b), the press pins 2 and 11 serving also as means for thetransfer of heat or of ultrasonic energy or, when connected with a highfrequency generator, it may serve as condensor for the production of ahigh frequency alternating field.

The bonding agent 3, 3 is melted by means of heat, or by the energy fromultrasonic waves, or from a high frequency field, and flows into thelayers 15 and 16 of 4 the fabric, resulting in their being bondedtogether on cooling (FIG. 2c).

In the example illustrated in FIGS. 31: to 30, the mass of bonding agent17 is in the form of studs and each preferably tapered to a point at thebottom so that they can penetrate more readily into the layers 18 and19. It can be seen from the drawing that the layers of fabric may befolded over at the seam.

In the example shown in FIGS. 4a to 40, the bonding agent is in the formof a wire 20, preferably of thermoplastic resin which is wound off areel or roll, not shown, and is guided in a vertically reciprocatingnozzle-like head 21. The head 21 contains a piston 22 which in turnmoves claw-like pressure members 23, 24-. When the head 21 moves down(FIG. 4) it moves the piston 22 with it, but the stroke of the piston 22is greater by the amount 25 than thestroke of the head 21, so that theclaw-like pressure members 23, 24 press the lower piece 26 of the wire20 into the layers 5, 6 of the fabric owing to the partially conicalshape of the interior of the head 21 and shear off the wire 20 in such away that one end 27 of the wire is at the same time tapered to a point.

The piston 24) and the pressure members 23, 24 serve at the same time totransmit heat impulses or ultrasonic energy to the piece of wire 26 oralternatively they may form, together with the supporting plate 9, acondensor for the production of a high frequency alternating field; thepiece of wire 26 which is pressed into the layers 5 and 6 of the fabricis melted by means of heat impulses or by ultrasonic waves or by heatingby high frequency and flows into the layers of fabric 5 and 6, bondingthem together on cooling (FIG. 4c).

During the upward stroke of the head 21 and the piston 22 (see FIG. 4a)the wire. 20 remains stationary, i.e., the claw-like pressure members23, 24 diverge again, slide upwards by a controlled, predeterminedamount along the wire 20, and then take the wire with them again on thedownward movement (FIG. 4b), shearing the wire off in the process.

The process of introducing the pieces of bonding material ofthermoplastic resin or the like may be separated either spatially or intime or both from the process of effecting a bond by heating or thelike. This method would be used if, for example, there is a risk of thetools which introduce the bonding agent being raised to too high atemperature by the heating process. Such a separation of these steps maybe carried out according to the invention in that, for example, anelement which is mainly concerned only with heating and therefore withglueing or bonding together the parts of the fabric supplied to it, isplaced in the path of the seam at a predetermined distance, which mayeven be adjustable, behind the member which introduces the bonding agenteither by stitching or some other means. Thus, for example, the seamwhich already contains the bonding particles but is not yet bonded isguided through a preferably strictly localized high frequency field or afield of ultrasonic waves or a source of heat. In this case,intermittent control of the supply of energy which gives rise to thebonding is not absolutely necessary.

In order, for example, to be able to take into account different speedsin the running of the seam, it is preferable to provide, in accordancewith the invention, a device which makes it possible to adjust theintensity of the flow of energy which effects the bonding or the like independence, for example, on the speed of running of the seam.

FIGS. 5a to Sc show a modification embodiment of the invention forproducing a pseudo single chain stitch seam. Again there are providedthe head 21, the piston 22, the claw-like pressure members 23, 24, thewire 20 of thermoplastic resin, the layers of fabric 5, 6, the needleplate 7, and the supporting plate 9 inserted in the latter.

This process, which is otherwise similar to that shown in FIGS. 4a to40, is to bind an upper thread, e.g. of textile material, such as yarnor twine 28 with the layers 5, 6 of fabric by means of the piece 26 ofthermoplastic wire 20 which has been introduced, so that the pseudosingle chain stitch seam is produced (FIG. 5c).

According to FIGS. 6a to 60, a stronger two-layered web 32, 33 is firstperforated in a preceding working step. The web 32, 33 may run, forexample, from left to right. As soon as the hole 34 has reached theposition underneath the device for the thermoplastic bonding of upperthread 35 and lower thread 37, the pointed end of the thermoplastic wire20 is severed by suitable means mounted in the head 21, in such a waythat a stud shaped piece 26 is cut 05 and is pressed, according to FIG.6b, into the hole 34 by the descending head 21, with the cooperation ofa finger 36 which acts on it from underneath in the opposite direction;the upper and lower threads are gripped between these parts 26 and 36 inthis region and are bonded together by heating the stud 26 ofthermoplastic material, as already mentioned, the final bonding particlebeing a kind of thermoplastic sphere (FIG. 60) which always unites theupper thread 35 to the lower thread 37 in the perforation 34.

According to' FIG. 7, the plate 12, which is cut to the appropriate sizeand shape, carries the two layers 15, 16 of fabric which are to bebonded together. The pseudo lock stitch steam is formed by the upperthread 35 and the lower thread 37. A point glueing or similar union bythermoplastic agent takes place which, in the example shown, results ina spherical connection between the upper thread 35 and the lower thread37. It is supplied through corresponding ducts whereby the thermoplasticmaterial is supplied in the form of small spheres 3, 3, both from belowand from above, or if necessary, only from one side. The processconsists in that the thermoplastic spheres 3, 3 are taken uprespectively by the upper press pin 2 and the lower press pin 11, whichcarry out suitably controlled movements in opposition to each otherwhich are adjusted to the stepwise movement of the fabric feed, and thespheres are pressed into the fabric, which is not necessarilyperforated, and take with them the corresponding parts of the upperthreads 35 and the lower thread 37 which are pressed into the fabric atthe same time and are united by the thermoplastic connection 3". In theconnecting process, the sphere or the like of thermoplastic material isadequately softened by means of a high frequency generator (not shown)or some other known means of heat supply.

FIG. 8 shows an analagous process for the production of a pseudo singlechain stitch seam. In this case, there is no lower thread, the upperthread 28 (as in FIGS. 5a to 5c) is fixed into the fabric layers 5, 6 inthe manner similar, to that used in the previous example so that, inparticular, a connection between the lower layer 6 of fabric and theupper thread 28 is formed.

A further embodiment of the invention is explained below with referenceto FIGS. 9 to 14.

Just like in an ordinary sewing machine, a needle 41 (FIG. 9) movesupwards and downwards, and an upper thread 43 is threaded through theeye 42 of the needle. Layers 44, 45 of fabric which are to be united aremoved, exactly as in an ordinary sewing machine, by a fabric feed whichis not shown, on the needle plate, which is also not shown.

While the fabric feed is in the position of rest the needle 41 (FIG.penetrates so deeply into the layers 44, 45 of fabric that the upperthread 43 forms a loop 46, which projects below the lower surface 47 ofthe layer 45 of fabric.

The needle 41 is rotated about a small angle (FIG. 14) so that the eye42 of the needle is at an angle to the direction of feed of the fabricand a tangent to the loop 46 of the upper thread 43 and to the needle 41gives a straight line A-B which is parallel to the direction of feed ofthe fabric. The lower thread 48 is so guided on the 6 needle plate,which is not shown, below the layer of fabric 45 that like the straightline A-B it is in contact with the needle 41 and the loop 46 of theneedle thread.

A nozzle-like piston 49 moves obliquely up and down below the needleplate and through it. This nozzle-like piston 49 is split in front toform two lips 50 51 (FIG. 13). Inside, in the actual nozzle 52 (FIG. 13)or similar conveyance device, is contained a rapidly hardening bondingagent, for example thermoplastic resin 53. This thermoplastic resin 53is introduced in the form of a powder, granuale or wire into thenozzle-like piston 49 or some similar conveyance device.

By means of electrical heating or hot air or high frequency current orby some other means, the front part of the thermoplastic material 53 isheated to the melting temperature so that this thermoplastic material 53is always in a liquid state inside the lips 50, 51 of the nozzle-likepiston 49 while the machine is in operation.

At the moment in the sewing operation at which the needle 41 (FIG. 10)has brought the upper thread 43 through the fabric layers 44, 45 and theupper thread 43 has formed a loop 46, and the lower thread 48 lies incontact with the loop 46 of the upper thread 43, the nozzle-like piston49 is moved upwardly (FIG. 11). The lips 50', 51 of the nozzle-likepiston 49 fork over the connecting point 54 between the upper and thelower thread 43, 48 (FIG. 13) to such an extent that the point ofcontact 54 is covered by the liquid thermoplastic resin 53 which isbetween the lips 50, '51 0f the nozzle-like piston 49.

The nozzle-like piston 49 then descends, returning to its startingposition (FIG. 12), having let a blob 55 of thermoplastic resin at thepoint of contact 54. This quickly sets and thereby establishes theconnection between the upper thread 43 and the lower thread 48 (FIG.12).

As the sewing proceeds, the needle 41 again ascends, the upper thread istensioned so that the bonded region is pulled into the layers of fabric44, 45 and no longer projects below the layer of fabric 45 (FIG. 12).Thus, a portion of the seam is completed, and the sewing cycle startsagain from the beginning, as described above. Continued operationresults in a pseudo lock stitch seam.

As many changes could be made in the above method and construction, andmany apparently widely different embodiments of this invention could bemade without departing from the scope of the claims, it is intended thatall matter contained in the above description or shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

Having thus described our invention, what We claim as new and desire tosecure by Letters Patent of the United States is:

1. A supply device for introducing a mass of thermoplastic material intoeach of a succession of recesses in a plurality of superimposed fabricmembers comprising in combination a housing with a bore therethrough, aram mounted for reciprocation in said bore, means for supplying adiscrete mass, such as a shaped solid plug, of thermoplastic bondingmaterial to said bore for ejection by said ram support means positionedadjacent the outlet end of said bore and slightly spaced therefrom andmeans connected to said ram for heating said thermoplastic material.

2. A supply device for introducing a mass of thermoplastic material to asuccession of recesses in a plurality of superimposed fabric members,comprising in combination a housing with a bore therethrough and a ducttherein, a ram mounted for reciprocation in said bore, said bore andsaid duct being so interrelated that discrete masses of thermoplasticbonding material fed in succession to the duct pass one by one into thebore for ejection by the ram on reciprocation by the latter supportmeans positioned adjacent the outlet end of said bore and slightlyspaced therefrom and means connected to said ram for heating saidthermoplastic material.

3. A supply device as set forth in claim 2 further comprising means forsevering said discrete masses from a continuous length of material.

4. A supply device for introducing a mass of thermoplastic material to asuccession of recesses in a plurality of superimposed fabric memberscomprising in combination a housing with a bore therethrough, a ram,having a duct therethrough, mounted for reciprocation in said bore, saidduct being adapted for the supply, in succession of discrete masses ofthermoplastic bonding material to the bore for ejection by the ramsupport means positioned adjacent the outlet end of said bore andslightly spaced therefrom and means connected to said ram for heatingsaid thermoplastic material.

5. A supply device as set forth in claim 4 further comprising means forsevering said discrete masses from a continuous length of material.

6. A supply device for introducing a mass of thermoplastic material to asuccession of recesses in a plurality of superimposed fabric members,comprising in combination a housing with a bore therethrough, a rammounted for reciprocation in said bore, cutting means associated withsaid ram adapted to grip a continuous length of thermoplastic materialand, at one end of the ram stroke, to sever a discrete mass therefromfor ejection from the bore by said ram support means positioned adjacentthe outlet end of said bore and slightly spaced therefrom and meansconnected to said ram for heating said thermoplastic material.

7. A supply device as set forth in claim 6 further comprising acounter-pressure plate disposed adjacent the ejection end of said boreto allow passage of said superimposed fabric members.

8. The combination set forth in claim 6 in which said support meanscomprises a second supply device identical to the first supply device,said supply device being symmetrically disposed With their bores in lineand the ejection ends spaced apart to allow the passage of superimposedfabric members and means for heating the thermoplastic material fromeach supply device.

References Cited UNITED STATES PATENTS 834,261 10/1906 Chambers 1282l71,262,732 4/1918 Andrews 128217 2,505,906 5/1950 Merritt 227 2,621,65512/1952 Olson 128-217 EARL M. BERGERT, Primary Examiner.

DOUGLAS I. DRUMMOND, Examiner.

1. A SUPPLY DEVICE FOR INTRODUCING A MASS OF THERMOPLASTIC MATERIAL INTOEACH OF A SUCCESSION OF RECESSES IN A PLURALITY OF SUPERIMPOSED FABRICMEMBERS COMPRISING IN COMBINATION A HOUSING WITH A BORE THERETHROUGH, ARAM MOUNTED FOR RECIPROCATION IN SAID BORE, MEANS FOR SUPPLYING ADISCRETE MASS, SUCH AS A SHAPED SOLID PLUG, OF THERMOPLASTIC BONDINGMATERIAL TO SAID BORE FOR EJECTION BY SAID RAM SUPPORT MEANS POSITIONEDADJACENT THE OUTLET END OF SAID BORE AND SLIGHTLY SPACED THEREFROM ANDMEANS CONNECTED TO SAID RAM FOR HEATING SAID THERMOPLASTIC MATERIAL.